Modern aircraft include many electrical and mechanical devices which are controlled from remote locations within the aircraft. According to current aircraft design practice, aircraft control systems employ dedicated point-to-point electrical wiring connections between system controllers and each of the various load devices they control.
FIG. 1A depicts a conventionally-wired system 100 of the prior art. Separate one-way single purpose wires are run from a system controller 12 in the nose of the plane to each of a plurality of remotely accessed load devices 10a through 10g. The system controller 12 transmits control signals to the load devices via these one-way point-to-point wiring connections.
However, as these aircraft systems grow, both in size and complexity, there is the drawback that the traditional method of direct point-to-point wiring has become excessively complex, unwieldy and expensive, as a considerable amount of wiring is required in order to connect the various elements. For example, the Airbus A380, the largest of the new airliners, carries approximately 300 miles of electrical wiring. This translates to substantial additional weight and increased fuel costs.
The large number of point-to-point wiring connections in close proximity to each other has also resulted in problems due to excessive heat generation, and wire signals interfering and crossing with each other. Indeed, some incidents (including a few air crashes) have directly resulted from electrical wiring problems within an aircraft. These problems with the conventional point-to-point connections are only exacerbated as the number of load devices in modern aircraft increases.
Moreover, conventional aircraft wiring systems are further complicated because of the distinction often made between traditional load devices, which are only presumed to receive control signals from system controllers, and sensor devices, which are only presumed to transmit signals back to the system controllers. Based on this distinction, sensor devices in an aircraft are often provided with their own one-way point-to-point wiring connections to the system controllers, separate and distinct from the wiring connections between the traditional load devices and the system controllers. Thus, the total amount of point-to-point wiring in the aircraft is increased.
For example, FIG. 1B depicts a conventionally-wired system 101 which is similar to system 100 in FIG. 1A, except that sensor devices 10x through 10z transmit signals back to the system controller 12. These sensor devices use one-way point-to-point wiring connections to return information back to the system controller.
This aspect of current wiring systems has the further drawback that it is often not feasible to transmit data to a sensor device or receive data from a traditional load device, or to transmit data directly between sensor and/or load devices.
U.S. Pat. No. 6,664,656 proposes an aircraft electrical power distribution network wherein one-way point-to-point wiring is provided between the loads and remote power distribution units (which are connected to system controllers), and similar one-way point-to-point wiring is provided between sensors and remote data concentrators (which are also connected to the system controllers).
In such a system, the amount of wiring is still relatively high, due to the use of the point-to-point wiring connections that cannot be shared between loads and/or sensors.
Further, the one-way nature of the wiring prevents the ability of the loads themselves to transmit data back to the remote power distribution units, as well as the ability of the sensors themselves to receive data from the remote data concentrators, and the ability of any load/sensor device to transmit data directly to another load/sensor device.
There exists a need for an improved approach for efficiently and directly controlling a plurality of devices in an aircraft, with a simpler control system that uses less wiring than conventional methods.